Pump



vJune 12,'1928. 1,673,261

c. R. MEsToN ET AL PUMP Filed July 1o, 1926 5 sheets-sheet 1 June 12, 1928. 1,673,261

c. R.. MEs-roN ET Al.

PUMP

uly 1 0, 192e s sheets-sheet 2 June 12, 1928. 1,673,261

C. R. MESTON ET AL INVENTOR5 Wa/'lq F?. Mesto/1 ila/r IK Me: to?? Y BY f mi 92 25 86 N4 am' Patented June 12, 192s.

f .UNITED STATES PATENT oFFlcnv CHARLES B. HESTON .AND ALECK W. MESTON, OF YONKEBS, NEW YORK, ASSIGNO'BS-TO THE STACOLD CORPORATION, OF NEW YORK, N. Y., .A CORPORATION OF NEW YORK.

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Application led July 10, 1926. Serial No. 121,515.

This invention relates to pumps and par- Y .ticularly to air or gas pumps such as are used in refrigerating apparatus. i

The invention has been particularly worked out in connection with pumps utilizing intermeshing gears for pumping air or as. With this type of pump, it is essentialt at the gear teeth fully intermesh and that there` be no leakage of air or gas around the teeth in the casing at the outlet sidel of the pump or leakage from the casing around the pump shaft. When the pump is ,used as a high pressure pump, it is very diiicult to prevent leakage of air or gas from the discharge side of the pump.

Also, in pumps of this character, when oil is used as the sealing liquid, a certain amount of oil will leak from the high re'ssure side to the low pressure side o the pump. This oil becomes impregnated to a reater or less degree with the gas or rerigerant when the pump is used in refrigerating apparatus and this is carried back with the o1l. The" oil and refrigerant tend 4 panding, thus taking up the space that.

should be taken by the intake gas.

v In the usual constructionof pumps of this type, the oil and impregnated gas that leaks to the low pressure side of the pump passes into an elongated cavity' and there the .gas 40 or refrigerant has an opportunity to separate from the oil.

Furthermore, the high pressure acting on the pump elements tends to exert a thrust thereon and cause wear of the gears and contacting parts of the pump.

The linvention has for its salient object to provide a pump so made as to obtain extreme accuracy in construction ata minimum manufacturingcost. f

Another object of the invention is to provide a pump of the character described so constructed thatthere will be as little leakage as possible at the outlet `or high pressure side of the pump.

.Another object of the invention is -to provide a construction by means lof which the thrust on the gears can be regulated to maintain'the gears and casingor contacting parts in contact at the discharge end of the pump, thereby preventing leakage.

Another object of the invention is to provide a pump so .constructed that any oil and impregnated gas that leaks from vthe hi l1 pressure to the lower pressure part of t e pump will be trapped and prevented from escaping into the intake.

Further objects of the invention will ap# pear from the following specification taken in connection with the drawings, which form a part of this application, and in which:

Fig. l is a sectional elevation of a .pump constructed in accordance with the inven tion- 2 is a sectional elevation taken sub stantially von line 2-2 of Fig. 1;

Fi 3 is a. sectional elevationA taken substantlally on line 3--3 of Fig. 1;

Fig. 4 is a sectional elevation similar to Fig. l but showing a diiferent manner of regulating the pressure of the gears against the endyplate at the discharge side of the Pump;

F1g.r5 1s a view similar to F1g.4 but showing still another manner of regulating the thrust of the gears against the end wall of the casing;

Fig. 6 is a View similar to Fi 3 taken substantially on line 6-6 of Fig. 7 and showing a dili'erent'manner of introducing the intake uid into the pum i and Fig. 7 is a sectional elevation taken substantially on line 7-7 of Fig. 6.

The invention brieiy described consists of a`pump comprising a casing bored to receive the gear elements and bearingvplugs and bushmgs for the gear elements. By

vmounting the gears and shaft bearings -in straight bores, the bearings, bushings and gears will be posltlonc'd 1n accurate allnement thus providing extreme accuracy at a mini?A mum of expense in manufacturing.

Means is also provided for so regulating the thrust on the gea-rs that the gears will be maintained in contact with the end plate of the casing at the outlet lor discharge ends thereof, thus preventing leakage.

In one embodiment of the invention the pump intake or low pressure side is so constructed that any oil and limpregnated gas is trapped in the teeth and prevented from escaping. The intake is located at the ends of the teeth and does not extend longitudinally or parallel to the axis of the gears as in the usual construction.

Further details of the invention will appear from the following description.

The pump casing consists of a body portion 10 and end plates 11 and 12. The bod portion is preferably cast in a solid-bloc and is bored longitudinally to form straight bores 15 and 16. (See Fig. 1.) The bores 15 and 16 as illustrated, consist of overlapping cylindrical openings which intersect in a common plane 17. A

There is positioned at each end of each bore a bearing box or plug 2O and in these bearing boxes or bearing plugs may be mounted bushings or bearings 21. If desired, the tWo plugs at each end of the bores could be made in one piece. The bushings may be rotatable or stationary, as desired. The bearing boxes or plugs 20 have substantially cylindrical outer surfaces but are formed with flat sides 22 adapted to be positioned in alinement With the common 'plane 17.

The pumping elements consist of a pair ofintermeshing gears 25 and 26, spiral gears lbeing illustrated. The gear 25 is mounted 4on a shaft 27 and the gear 26 is mounted on a shaft 28, the shafts .27 and 28 being mounted 'n the bearings 21 carried by the plugs 20.

The straight bores thus receive thc gears, shafts and shaft bearings and because of this construction the elements specified can be accurately alined.

. As shown in Figs. 2 and 3, the bores A15 and 16 intersect in a knife edge 30 at the high pressure or discharge side of the pump and it is very essential that the gear teeth 31 and 32 of the gears` 25 and 26 accurately fit the casing vat this knife edge so as to prevent escape of the high pressure air or gas. This is accomplished by locating the plugs or bearing boxes 20, the gears, and gear shafts in the straight bores 15 and 16.

The air or gas or other substance to be pumped is admitted to the casing body 10l through a conduit 40 land opening 41 formed? in the casing. In Fig. 2 the opening 41 communicates at itsl inner end with a recess 42 formed in the casing body opposite the knife edge 30.

The air .or gas 4or otherA substance being pumped leaves the casing body throng opemngs 45 formed in the plugs 20 and communicating with discharge conduits 46.

In the particular pump construction illustrated, the body l10 of the pump easing 1s mounted` on a base plate 50 whic in turn is mounted on and forms the top for a cooling reservoir or chamber 51. Theca'sing body the cooling chamber or reservoir 5l. The

cooling -luid enters the reservoir 51 through a'conduit 57. and leaves the casing by a conduit 58 Which is secured to plate 55 and extends therethrough.

In the embodiments of theinvention illustrated, the liquid used for sealing and lubrieating the pump elements enters the cooling reservoir or chamber 51 through a conduit 60 and passes around a coil 6l disposed 1n the chamber 51 and outwardly vthrough a conduit 62. i

In the embodiment of the invention illustrated inFigs. 1 to 3 inclusive, the seal-ing and lubrzcatmg liquid passes from a conduit 62 into a conduit 63 having a by-pass 64 leading to a recess or pocket 65 in theend plate 11. 'lhe conduit 63 also communica'tes with a conduit 66 which in turn communicates With a recess or pocket 67 yformed in the end plate 12.

- The pockets 65 and 67 are disposed opposite or in alinement with the. plugs 20 and bushings 21 and grooves 68 are formed 1n the bushings to conduct the lubricant and sealing liquid inwardly along the inner sur-- face ofthe bushings. Each of the bushings 21 has formed on its inner end an annular v Fig.'1 that the grooves 69 on the bushings 21 at the right hand end of the gears has a larger-outside diameter than the groove 69 in the inner end of the bushing atl the left hand end of the gear.

By varying the dimensions of the bushings and of the grooves, thev amount of pressure between the bushings and the ends of the gears can be varied.

For instance, the bushings at the right hand end may be made thicker or may have a greater outside diameter than the bushings at the left hand end. If the bushings so .constructed are rotatable and float, then the pressure of the liquid in the pocket 65 Will force the bushings against the rlght hand end of the gears and as the pressure is exertllo If the bushings are non-rotatable or stai tionary and longitudinal groovesv such as 68 are provided communicating` With the annular groove 6 9, then the dimensions of the annular grooves will determine the area over which ressure is exertedon the gears and if, as ilustrated, the grooves 69 are larger thereof.

It is desirable that the pressure toward the left in Fig. 1 be greater than the pressure toward the right in order vto cause the left hand or delivery ends of the gears to be maintained in close contact with the bushings and plugs. This result can be obtained 1n various ways as pointed out above.

' 75 at the right hand end of the andl 26 have a greater diameter t an the In Fig. 1 there are shown also a plurality of small or minute conduits 70 which lead from the pocket 65 to the right hand ends of the gears and 26. These passages conduct the sealing liquid to the gear teeth and seal the teeth, thereby preventing loss of pressure.

In Fig. 4 the pressure on the gears is regulated by varying the size of the gear shafts at the two ends of the gears. For instance, it will be noted that the shafts or trunnions ears 25 shafts 76 at the left hand ends of the gears. The lubricating and sealing liquid is led to pockets 77 in casing end plate 11 throu h conduits 8O and 81, and to Aa pocket 78 in t e end plate 12 through-a conduit 82. Also the sealing liquid is conducted from a conduit 80 through 'a conduit 83 to the shaft 76 -.which is; extended through the end plate 12 and constitutes the drive shaft.

It will be evident that the pressure toward the left in Fig. 4 is eater than the pressure toward the right an thus the left hand faces or the delivery end of the gears will be maintained in close contact with .the end plate 12.

In Fig. 5 the gears 25 and 26 are carried by the Shafts and se. The' right hand ends ofthe shafts 85 and 86 are surrounded by bearm bushings or plugs 87 and extend throught e plugs, the outer ends of the shaftsbeing surrounded by springs88 interosed between the end plate 11 and the ushmgs 87. The shaft 86 at its opposite end extends into a bearin pocket 90 and the opposite end of the sha t 85 extends outwardldy through the end plate 12 and is conneote to the drive shaft.

The sealing and lubricating liquid enters -with t e pocket at the -.right hand end of the casing and conducts-the lubricant to the left hand end of the shaft 85. I

From the showing in Fig. 5 it will be evi- `de nt that the` pressure on the right hand 'end' Vof thev gears which y is transmitted.l through the bushings 87 will be greater the pressure toward the .right or the prea-v sure on the left hand ends of the gears, thus maintaining the gears in close contact with the end plate 1 It will be understoodA that-the sealing liquid passes from the tpump with the air'or gas pumped, is extracte from the gas in a separator and returns to the coil 71 through pipe i in the teeth the oil and impregnated gas that leaks Vfrom the high pressure side, thus preventing the escapement thereof.-

This is accomplished by extending the casing to a knife edge at the low pressure side andv extending the knife edge to a point such as 96 adjacent the ends of the gears. The plugs are preferably grooved as shown at 97 and 98 at this end of the gears and the intake or fu y out of gear permitting the teeth to take u the maximum ca acity of the gas, in add1tion to whatever oi and impregnated gas is tra ped in the teeth. l .v

Althoug in the particular form of the invention illustrated, the intake portsare `shown at the opposite ends of the gears from the discharge or high pressure end of the gears, it will be understood that these ports may be located intermediate the ends of the gears or at the same end as the discharge port or ports if desired.

be cut o before thev gear teeth go into mesh glas reaches the teeth when they are open I and before the sealing liquid or oil .is in-4 jected into the teeth.

From the .foregoing specification itwill be seen that by means ofthe structure described a iipump has 'been provided that will operate e ments will be maintainedin close contact with the casin at vthe delivery ends thereof. Furthermore, y trapping the oil and 1mpregnated vgas in the teeth the esca ement of the gas tothe intake is prevente the capacity of the pump is increased and the elli,v ciency of the vacuum is increased.

Although certain specific embodiments of ciently and inwhich the gear elethe inventlon have been particularly shown and described, it will be understood that the invention is capable of modification and that changes in the construction and in the arrangement of the various cooperating parts may 'be made without departing from the spirit or sco e of the invention as ein'v pressed in the fo owing claims.

What we claimis:

1. vA. pump comprising a casing, inter.- meshing gears mounted therein, means for conducting lubricating and sealing liquid to the lends of vsaid gears :and means-for transmittin the pressure ,of 'thelsealing liq- .uid to sai gears, said means being con.

A:sus

structed and arranged to exert a greater pressure against one end of the gears than against ythe other end thereof.

2. A pump comprising a casing. gear shafts therein, intermeshing gears mounted on said shafts, means for conducting lubricating and sealing liquid to the ends of said gears and means including bushings surrounding said gear shafts for transmitting the pressure of the sealing liquid to said gears, said means being constructed and arranged to exert a greater pressure against one end of the gears than against the other end thereof.

3. A pump comprising a'casing, a pair of intermesliing spiral gears therein adapted to discharge air or gas at high pressure from the ends thereof, and means for conducting sealin and lubricating liquid.v to said gears, said means being constructed and arranged to press the ends of the gears at the discharge side of the pump against the casing.

4. A pump comprising a block having arallel bores therethrough, end plates closing the ends of said bores, gear shafts and gears mounted in said bores, rotatable bushings in said bores vsurrounding said gear shafts, said end plates having pockets .disposed in alinement with said bores and means for conducting lubricating and sealing liquid under pressure to said pockets, thereby pressing said bushings against said gears, said bus ings being so constructed and arranged that ka greater pressure is exerted on the gears in a direction toward the high pressure side of the pump than in the opposite direction.

5. A pump comprising a block having parallel bores therethrough, end plates closing the ends of said bores, gear shafts and gears mounted in said bores, rotatable bushings in said `Ybores surrounding said gear shafts, said bushings having annular grooves in the ends thereof adjacent the gears, said end plates having pockets disposed in alineinent with said bores and means for conducting lubricating and sealing liquid under pressure to said pockets, thereby pressing said bushings against said gears, said busliings being so constructed and arranged that a greater pressure is exerted on the gears in a direction toward the high pressure side of the pump than in the opposite direction.

6. A pump comprising a casing, having substantially parallel straight bores therein,

bearings slidubly mounted iii the ends of said bores, gear shafts mounted in said bearings, and means for conducting liquid under pressure to the ends of said bearings.

7. A pump comprising a casing, having parallel bores therein, plugs in the ends of said bores, shafts rotatably mounted in said plugs, gears carried by said shafts and abut" ting said plugs, said gears being disposed in intermesliing relation, an out-let conduit at one end of the gears, the plugs at one end of the gears having grooves opposite portions ofthe fears that are out of mesh and an inlet conduit 4communicating with said grooves.

ln witness whereof, I have hereunto set my hand this 6th day 0f July, 1926.

CHARLES R. MESTON. In Witness whereof, l have hereunto' set my hand this 6th day of July, 1926.

ALECK W. MESTON. 

